In connection with an aircraft engine, a seal may be used to isolate, or reduce a flow of fluid between, two or more interfaces that are separated by the seal. The conditions in which the seal operates may vary and frequently are expressed in terms of temperature, pressure, and rotational speed.
An operation requirement for aircraft engines frequently includes the ability to tolerate eccentricity between a rotor axis and a shoe of the seal. Large displacements may need to be accommodated while still providing an adequate resonant frequency margin.